Microstructure and Ferroelectric Properties of (Na,K)(Nb,Sb)O3 Ceramics Substituted with LiTaO3

In this study, in order to develop lead-free composition ceramics for piezoelectric actuator, (Na,K)(Nb,Sb)O3 ceramics modified with LiTaO3 were prepared by a conventional mixed oxide method. The influences of LiTaO3 on the microstructure, dielectric, ferroelectric, and piezoelectric properties were investigated. All the specimens showed a pure perovskite phase and no secondary phase could be confirmed from the XRD patterns. The SEM images indicate that the grain size increased with increasing the content of LiTaO3-substitution. Excellent physical properties of piezoelectric constant (d33) = 280 pC/N, electromechanical coupling factor (kp) = 0.534, dielectric constant (ϵr) = 980, and density (ρ) = 4.50 g/cm3 were obtained from the composition ceramic with x (LiTaO3) = 0.0375. These results indicate that the composition ceramic is a promising lead-free piezoelectric material for actuator applications.